Thyroid UK


Are there any known issues regarding the use of a general anaesthesia and levothyroxine? I am due an operation where a general anaesthesia will be administered. It is not a thyroid related operation. I am currently using 175mcg Levothyroxine daily.

Are there any issues that I should discuss with the surgeon- to refresh their knowledge of patients with hypothyroidism, before the operation- from a hypothyroidism point of view- from how Levothyroxine interacts with general anaesthesia to possibly delayed recovery?

Thank you for your replies!


11 Replies

You need to be in discussion with the anaesthetist.

I know next to nothing but we have fairly recently had someone having their operation delayed due to their thyroid levels. So do NOT delay getting in touch. Hopefully someone else will pile in here.



They just checked everything at my pre op and before surgery and I had to take my meds as normal


HI I had surgery (on my knee) in october and didnt take my levo that morning on surgeons advice and i also had a general anaesthetic,,let them know before hand and they will advise as every person is different...


I took mine as normal and everything was fine :-)


Levothyroxine treatment does not have any impact on anaesthesia. You will be nil by mouth for a specified number of hours before the operation. If you surgery is in the morning you could take your dose earlier than normal rather than missing it. On the other hand, missing one dose of levothyroxine is not normally of any clinical significance.

You should be given the opportunity to speak with the anaesthetist before the operation.


Levothyroxine treatment does not have any impact on anaesthesia..... if the dose is correct and you are stable.


I think that you can't have ketamine in the anaesthetic but I'm sure the anaesthetist will know this. I'm no medical expert- just going by my own experience. Good luck with your operation.


I agree with all of the above. Since I have always taken my Levo at night, I have not even had to miss a dose. I have had at least four general anaesthetics since I have been on Levo with no ill effects whatsoever.

Even so, as Bobbin2 says, you should have the opportunity to speak to the anaesthetist before the operation because any issues would always be the concern and responsibility of the anaesthetist. If, for example, you still have some of your hypo symptoms, you could mention these to him/her.

You will have had all the usual checks in preparation for the anaesthesia and if any potential problem were to be revealed by these checks, they would tell you.

Marie XX


I have had numerous GA ops over the years after having a nodular goitre removed at 16 years old. I am 62 now. I have always been told to take my levo. I am instructed to stop my anti inflammatories 14 days before though. I also get no side effects from a GA except that I am very hungry!

I wish you well with your forthcoming op.


I've had 2 major surgeries and. 1 normal op since thyroid removal and was fine x


Hey Dr Peatfields book says that the drugs they give you containe Bromide which buggers up your thyroid and you really should take more meds.. also the anti-biotics attack your thyroid so best take your temperature.. if you're low... then up your meds for a few days to compensate.. keep going by the temperature, when it comes back up, you can go back to your dose.. (or if you get any Hyper symptoms)


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